Supporting User Input

[sinanspd]

Any thoughts on adding support for user input?

I understand the downside that is, the library will likely have to come with cats-effect by default, instead of being optional (unless this also was a separate module).

But I think it would be vital to enable complex tooling and allow the user to build complex flows.

A very simple example would be

$ decline-clt  diff-push-merge 
     username: ....
     password: ...

    Success!

Furthermore, it would enable something like this ticket => #171

To be turned into

$ decline-clt generate-file
    Enter File Name: ...
    Choose file type:
        [.] Class
        [.] Trait
        [.] Object

[Ben Kirwin]

hmm... i don't think i understand the proposal, exactly. decline users can already write apps that take user input, using either cats-effect or impure styles. i can imagine a support library for user input being useful, but i don't see how baking it in to the cli parser makes it any easier! is there something that decline is preventing you from doing here, or is there some synergy i'm missing? Le dim. 24 mai 2020 à 16:50, sinanspd <[e-mail]> a écrit :

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Any thoughts on adding support for user input? I understand the downside that is, the library will likely have to come with cats-effect by default, instead of being optional (unless this also was a separate module). But I think it would be vital to enable complex tooling and allow the user to build complex flows. A very simple example would be `$ decline-clt diff-push-merge username: .... password: ... Success! ` Furthermore, it would enable something like this ticket => #171 <#171> To be turned into $ decline-clt generate-file Enter File Name: ... Choose file type: [.] Class [.] Trait [.] Object — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#172>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAMFXM3ZMILCG6YH7ZNNY3DRTGCBNANCNFSM4NJBI7YA> .

[sinanspd]

It is pretty easy to read single line input with cats-effect but I was thinking about more interactive options (checkboxes and list options, see attachement), in a composable manner.

Something along the lines of

sealed trait UserInput[A]
case class SingleLineInput[A](name: String, message: String) extends UserInput[A]
case class ListInput[A](name: String, message: String, choice: List[String]) extends UserInput[A]
case class CheckBoxInput[A](name: String, message: String, choice: List[String]) extends UserInput[A]

where A is a refined type for validation

We then have a few options to define a flow. I.e. a list of UserInput and saying something along the lines of following would execute the input questions in order and return the result

Opts.flow(value: List[String]).mapN{ (answer1, answer2, answer3, ...) => ...}

You could pass that in a subcommand

Command(
        name = "questions",
        header = "Ask User Some Random Questions"
    ) {
       Opts.flow(value: List[String])
    }

Just some quick thinking.. Various ways to model this, even potentially to allow nested dynamic Flows.

Frankly, I don't know what the goals of this library was when you created it but I feel like something like this would fit well.

[Ben Kirwin]

I don't think this benefits that much from being combined with the UNIXy command-line parsing stuff, and historically we've tried to keep decline pretty lean, so I think this is probably a no. A nice idea for another library though!